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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 6 September 2011 by Rob Painting, dana1981

Andrew Dessler, a climate scientist at Texas A&M University, has released a scientific paper (Dessler 2011) that looks at the claims made by two of a small group of "skeptic" climate scientists who regular SkS readers will be familiar with: Roy Spencer and Richard Lindzen. Both were co-authors on peer-reviewed papers released this year (Spencer & Braswell [2011] & Lindzen & Choi [2011]) which, once again, sought to overturn the orthodox view of climate. Dessler (2011) finds that the conclusions of these two papers are unsupported by observational data.

Spencer & Lindzen: Tipping reality on its head

The Spencer/Braswell and Lindzen/Choi papers have an unusual take on global warming: rather than warming causing a change in cloud cover (i.e. acting as a feedback to either increase or reduce warming), both papers claim that it's the other way around - changes in cloud cover cause changes in the surface temperature (in the present case, warming).

Spencer/Braswell and Lindzen/Choi look at the relationship between changes in ocean heat, cloud cover (directly affecting the amount of heat lost to space), and global surface temperature over recent decades. The idea is, if the change in surface temperature over that period is affected by changes in cloud cover, but changes of the surface temperature associated with the ocean warming are small, then changes in cloud cover must be driving the present global warming.

Dessler: Putting reality back on its feet

Putting aside the problems with their energy budget equation, Dessler looks at the values Spencer/Braswell and Lindzen/Choi use for their calculations. Rather than examine the data for two of the terms in their equation (heating of the climate by the ocean & change in cloud cover allowing heat to escape to space), Lindzen and Spencer approximate them from other observations, and their results rely heavily on assumptions about the size of these values.

Rather than rely on assumptions, Dessler uses other observational data (such as surface temperature measurements and ARGO ocean temperature) to estimate and corroborate these values. Dessler finds that, in contrast to Spencer/Braswell and Lindzen/Choi, the change in cloud cover is far too small to explain the short-term changes in surface temperature, explaining only a few percent of surface temperature change. In fact, the heating of the climate system through ocean heat transport is approximately 20 times larger than the change in top of the atmosphere (TOA) energy flux due to cloud cover changes. Lindzen and Choi assumed the ratio was close to 2, while Spencer and Braswell assumed it was close to 0.5.

Dessler finds that the short-term changes in surface temperature are related to exchanges of heat to and from the ocean - which tallies well with what we know about El Niño and La Niña, and their atmospheric warming/cooling cycles.

Spencer & Braswell: A classic example of cherrypicking

In order to claim that the climate models differ from observations when comparing the surface temperature and energy leaving the Earth at TOA with the lead-lag between them, Spencer/Braswell cherrypick observational data and model results that show the greatest mismatch (Figure 1).

Figure 1: Dessler (2011) reconstruction of Spencer & Braswell's figure 3, showing relationship between top-of-atmosphere (TOA) net flux and surface temperature, as a function of lag between them. The blue line is the observational data chosen by Spencer and Braswell. The red lines show other available observational data. The shading represents the two-sigma uncertainty of two of the data sets. The black lines show climate model results. The black lines with crosses show the climate model runs chosen by Spencer and Braswell in their paper.

The blue line in Figure 1 is the TOA and Hadley Centre surface temperature data chosen by Spencer/Braswell, and the red includes other datasets of the surface temperature. The black lines are the 13 climate model runs, with the 'crosses' indicating 5 of the 6 models analysed by Spencer/Braswell. Although Spencer/Braswell analyzed 14 models, they only plotted the 3 with highest and 3 with lowest equilibrium climate sensitivities.

In the process, Spencer and Braswell excluded the three climate model runs which best matched the observational data. Dessler found that these three model runs were also the ones which are among the best at simulating El Niño and La Niña, which is not surprising, given that much of the temperature change over 2000-2010 was due to the El Niño Southern Oscillation (ENSO). Thus Dessler concludes that

"since most of the climate variations over this period were due to ENSO, this suggests that the ability to reproduce ENSO is what's being tested here, not anything directly related to equilibrium climate sensitivity."

Violating the Laws of Thermodynamics

Dessler also examines the mathematical formula that both studies use to calculate the Earth's energy budget, and finds that it may violate the laws of thermodynamics - allowing for the impossible situation where ocean warming is able to cause ocean warming.

Much ado about nothing

The short-term change in surface temperature over the 2000-2010 period is a result of ocean heat being exchanged with the atmosphere (via ENSO). This in turn alters atmospheric circulation, which alters cloud cover, but the impact of cloud cover on surface temperature only explains a small percentage of the surface temperature change. Thus the lead-lag relationship between heat leaving the Earth at TOA and surface temperature reveals nothing about what is driving the short-term surface temperature change.

In short, the "skeptic" hypothesis that changes in cloud cover due to internal variability are driving global warming does not hold up when compared to the observational data. Once again we have two heavily-hyped "skeptic" papers that have failed to live up to their billing.

@dorlomin #2: As Big Tobacco proved, all the anti-AGW Spin Machine needs to do is create doubt and confusion within the general public in order to prevent government from taking action to address a problem.

The Spencer paper compares a 100 year model run against 10 year top of the atmosphere measurements, would I be correct in thinking that that 10 years would be influnced by sulphate areosols, methane and CFC levels, by the ENSO which may not come out as neuteral over 10 years and due to dropping solar forcing (although I am not sure about the latter as if it is a TOA measurement it should measure incoming shortwave light).

Thanks, Rob and Dana for this outline of Dessler's paper. Good to have.

BTW - I just popped over to Spencer's blog. From what I gather he is saying in his latest blog article is that to claim global warming will make droughts and floods worse than they would otherwise have been is a load of hooey.

And this man is supposed to be helping research climate? I suppose he has tenure, but surely that sort of scientific illiteracy would be grounds for a shift sideways to a clerical or TA role, if not the sack.

Dessler essentially admits they aren't measuring sensitivity, but ENSO. Dessler picked some models that do better modelling ENSO yet none of them drop into negative correlation. Understandable since models can't easily predict the pos/neg or neg/pos switch. So what we end up with is "And since most of the climate variations over this period were due to ENSO, this suggests that the ability to reproduce ENSO is what's being tested here, not anything directly related to climate sensitivity."

Dessler then tries to unglue himself from the failure of linear regression, lagged or not, by pointing out that temperature response controls ENSO which controls temperature. Thus, he states, "clouds did not cause significant climate change over the last decade" But the question we are trying to answer is are clouds forced by ENSO or a feedback from temperature change (i.e. climate change from CO2 forcing), and if feedback, what sign?

The answer from S&B11 is we don't know. Dessler does not answer that question either.

First, a post preempting everything that re-iterates how wonderful and indisputable he considers his own paper to be, and how nefarious must be the nature of his critics.

Second, today, a post on a completely different subject, but apparently aimed at undermining Dessler's credibility.

What I found most comical was the following quote from his first of the two posts, on the brouhaha over his own paper, where he in one breath says that funding by Big Oil is an urban legend, but then goes to accuse other scientists of fudging their own work to gain government funding. I swear, he just Poe'd himself.

And (BTW) we get no funding from Big Oil or other private energy interests. Another urban legend.

I hate to say it, but we need some sharper tools in our shed than we have right now. And the fresh eyes we need cannot have the threat of a loss of government funding hanging over their heads if what they find happens to disagree with Al Gore, James Hansen, et al.

Eric(skeptic) @ 8: that may be the question you would like answered, but it's definitely not the question that S&B11 was trying to answer, which was more like: are clouds causing ENSO (and any and all climate change)?

S&B postulated that clouds caused some of the ENSO temperature changes, not ENSO itself. Extending that to "climate change" is unsupported, also they did not quantify the amount of temperature change that was radiatively forced except very roughly (70/30). Their real conclusion is that it is not simple to extract cloud feedback (or even the sign) from temperature changes the way that the models are claimed to do.

On clouds, Dessler showed that their effect, one way or another, is trivial, so your proposed question of "are clouds forced by ENSO or a feedback from temperature change" is moot.

On ENSO, I don't at all see what your problem is. My understanding is that Spencer tried to treat ENSO events as climate change (temperature changes) in and of themselves, without reference to the mechanics that cause them. By ignoring those mechanics, he makes them seem like unrelated climate events controlled by clouds or other factors. To get better results in his claims about models, he also ignored those models that best handle ENSO events.

Lindzen did something similar, by treating annual swings in temperature that are caused by a local physical mechanism (ENSO) as if those were actual changes in the heat content of the earth-energy system over longer time scales. You just can't do that. It would be like rocking a parked car, and then claiming you can use that behavior to model how the car would accelerate away with the engine on and a driver behind the wheel.

Eric, there are a few key findings in this paper. One is that the heating of the climate system through ocean transport is ~20 times larger than energy changes due to cloud changes. A second is that while cloud changes can lead surface temperature changes, that's a result found in climate models as well, in which surface temperatures are an input.

We'll have a bit more on this tomorrow. The bottom line is that contrary to Spencer and Lindzen's claims, the climate is behaving as models expect, and short-term temperature changes are dominated by ocean heat transport, not cloud cover changes.

When a good chess player plays chess, instead of playing the move that maximises his advantage, he plays the move that minimises his opponents maximum advantage; on other words he plays in the expectation of best play from his opponent. A good scientist publishes his arguments in the same manner; instead of presenting the strongest argument he feels the evidence can support, he presents the strongest argument that an opponent can't refute. So if there are choices to be made in presenting the evidence, you don't make the choices that maximally support your argument, you make the choices that give the least support for your position. If you are right, the evidence should still be on your side even then, and you will have made your paper bullettproof. Roy clearly didn't do that here, he didn't choose the models that were most closely in accord with the data, but those that would clearly make his argument. As it happens those models also happen to be amongst the worst in terms of matching the observations. What he should have done is present the results for all of the models (so there can be no accusation of cherry picking) and then find out why some of the models fit the observations better than others. Unfortunately for him it appears that it is not climate sensitivity. If his scientific career were a game of chess, this move would be annotated with a "?!" at best.

S&B postulated that clouds caused some of the ENSO temperature changes, not ENSO itself

Actually, that is not clear Eric, b/c what Spencer is trying to argue is not clear. If you follow his online discussion (sorry, I cannot recall exactly where that was held off the top of my head, but I did find this), Roy's reasoning was almost incoherent and at times his statements are inconsistent. We know that clouds, especially deep convection, respond to the change sin surface winds and SSTs associated with ENSO, and those changes in cloud cover probably have some feedback.

And no comment from you Eric about the problems with Spencer and Lindzen's and Braswell's and Choi's thinking running into trouble with the conservation of energy.

"Their real conclusion is that it is not simple to extract cloud feedback (or even the sign) from temperature changes the way that the models are claimed to do. "

That may be, but that is most definitely not even close to how their findings have been spun and distorted, not only by the denial misinformation machine, but by Roy Spencer himself.

I have said this elsewhere on SkS, and it still applies today (especially after Spencer has now made a rather brazen defamation attempt on Dessler noted by Sphaerica @9):

"Spencer is now clearly using science as a political tool in his ideological and political vendetta against the IPCC and climate scientists who are rightly concerned about the impacts of us doubling (or even quadrupling CO2). I find that incredibly disturbing."

Spencer's actions of late also make his claims about being interested in advancing the science ring hollow.

Eric you noted on another thread that:"With such gross oversimplifications on both sides I can't help but think Spencer is arguing about nothing."

What do you mean by short-term exactly? People tend to think of the oceans changing temperature relatively slowly, so one should be clear about the time scale involved and what is causing the ocean to change on that time scale. I know this is alluded to in the post a few times, but the point must be clear that we are effectively talking about changes brought about by ENSO, no? My concern now is that some people might misinterpret, spin this to claim that ENSO is driving global warming....

I like this part from the body post,"Dessler finds that.... In fact, the heating of the climate system through ocean heat transport is approximately 20 times larger than the change in top of the atmosphere (TOA) energy flux due to cloud cover changes. Lindzen and Choi assumed the ratio was close to 2, while Spencer and Braswell assumed it was close to 0.5."

Let me see, should we go with "found using observations" or with the "assumptions" of ideologically driven scientists? ;)

Sphaerica, your understanding matches mine, but remember that one of Spencer's goals in the paper is to show that climate models do not match observations, specifically that the underestimate the radiative gain from a temperature change from ENSO. He can't really use another climate model to prove that some other climate model is different (more or less a tautology).

Albatross, I'm going to have to refresh my memory on the conservation of energy issue. I think we agree that what Spencer says online is different from the paper, specifically his claims about sensitivity. Dessler in his paper makes no such claims either. Spencer's accusations are unsupported because nobody is supressing his scientific claims about sensitivity since his paper has none and it was not supressed anyway.

Dikran your chess analogy is good, but keep in mind that Spencer's paper did not go out on any limbs that can be easily sawn off (he left that to his blog). In fact he can simply argue the dispute over model choices is more evidence that the models are wrong.

Eric (skeptic) wrote: "one of Spencer's goals in the paper is to show that climate models do not match observations"

Pity then that he didn't show the results obtained using the models that most closely matched the observations (which as Dessler shows lie within the error bars of the observations).

"Dikran your chess analogy is good, but keep in mind that Spencer's paper did not go out on any limbs that can be easily sawn off (he left that to his blog). "

No, if showing that the models don't match the observations was one of his goals then not showing the models that give the best match is a definite blunder (to continue the chess analogy)

Not considering the error bars on the observations is another easily sawn off limb.

"In fact he can simply argue the dispute over model choices is more evidence that the models are wrong."

That would be a ludicrous argument, and would demonstrate a complete lack of understanding of what the models actually say. The models cannot be expected to reproduce the exact course of chaotic features such as ENSO. Even if you had a model with perfect physics you would only expect the observations (taking into account the error bars on the observations) to lie within the spread of the model runs.

Dikran, the first thing I thought seeing S&B fig 3 is that of course the models aren't going to match the observations when the gain in the observations goes negative (i.e. a new ENSO cycle starts). The models can't in fact reproduce ENSO at all. Dessler's paper backs that up. Why would anyone expect the slope or gain or any other aspect of the ENSO response in the models to match observations? Also I don't see this new Dessler paper doesn't undermine Dessler 2010 in which he used a model to derive the cloud feedback to SST. Doesn't it now mean he must choose the "right" model to get the right results in Dessler 2010?

" I'm going to have to refresh my memory on the conservation of energy issue"
Please do.

"Dessler in his paper makes no such claims either.."
Correct, but surely you understand the implications of Dessler's findings in the context of feedbacks and climate sensitivity, and claims that climate sensitive low b/c of a negative feedback from clouds arising from some mystical force. Also, Dessler (2011) exposes the lengths that Spencer and Braswell went to try and mislead people concerning the veracity of the the models discussed in the IPCC reports. Perhaps that action is a reason to have SB11 retracted.

Eric (skeptic) wrote: "Doesn't it now mean he must choose the "right" model"

No, better not to choose models and if you are going to compare them with the observations, you need to take the uncertainties in both the models and observations into account. I don't know whether that was done in Dessler's earlier paper, but whether it was or not does not change the fact that the SB paper is dead in the water.

BTW it is not correct that the models can't track ENSO. The newest models are beginning to be able to make worthwhile decadal predictions. Even then, they can only do so if they are properly initialised so that they have matching ENSOs at the start of the prediction. However that doesn't mean the ones used in the study could, or were initialised so they could. The point is that Spencer would make himself look silly by claiming a model-data mismatch after (i) discarding the models that minimise the mismatch and (ii) discarding the observations that minimise the mismatch. As I said, that is not the "chess player" approach as he is ignoring data that do not support his conclusion, and so is easily refuted by Desslers Figure 1.

Just to be clear about models simulating ENSO. They can clearly be very useful tools for predicting the evolution of current events and perhaps the start of a new phase in the oscillation-- but that is all on a scale of less than a year or so. So the models can reproduce the ENSO.

What I was referring to @27 is AOGCMs running out 100 years most likely not being able to tell us correctly the timing of the next El Nino or La Nina, as those models do not have the luxury on real-time boundary conditions as current models used to predict the evolution of ENSO do.

Dikran do I have that more-or-less correct?

00

Moderator Response: [Dikran Marsupial] Yes, that is my understanding, expecting the ENSO of even the best model initialised a century ago to be in phase today is rather unlikely, to say the least. I suspect the very latest models can track rather longer than a year or so, or the modellers wouldn't be starting to get interested in looking at the skill of decadal projections.

Eric (skeptic) No. If the problem was that ENSO was the problem, then it would be reasonable to select the model runs where the modelled ENSO was close to the observed ENSO and then perform the analysis. This would effectively be controlling for ENSO.

However, the key point is that S&B11 is dead in the water because they cherry picked BOTH the models and the data that maximise the model-data disparity. Had they instead followed the chess player approach they would have looked at the choices that minimise the disparity as well and tried to work out what was the factor that caused the difference. It is what is known as skepticism, which should always start with self-skepticism. The harder you try an pick holes in your own arguments, the more likely they are to survive peer review and (at least) the first encounter with the research community.

That 3rd oder polynomial fit to the tropospheric temperature data is meaningless. But I am confident that Roy knows that and the intent of the graph, despite the caveat, is to mislead and/or allow people to make their own misguided interpretations. Spencer doing that is known as feeding fodder to the "skeptics" and those in denial abut AGW-- in fact, that seems to be one of the main goals of his blog nowadays.

Anyways, we'd better leave it at that for now, there are more important developments afoot such as Dessler (2011).

Radiative forcings (N) of temperature change could arise, for example, from natural fluctuations in cloud cover which are not the direct or indirect result of a temperature change (that is, not due to feedback) [6]. Examples of non-radiative forcing (S) would be fluctuations in the heat exchange between the mixed layer and deep ocean, or between the mixed layer and the overlying atmosphere.
Importantly, satellite radiative budget instruments measure the combined influence of radiative forcing (N) and radiative feedback (- λ∆T) in unknown proportions.

The first comment on this post hits the nail on the head. The only people who do not see the obvious "grasping at straws" here are those the paper was written for, and those people never read it. They just used it to promote a political agenda.

The science has reached the point that the few remaining skeptics in the academic world seem to be submitting papers for their political followers and not for their peers.

This could be dangerous if the journals start to dismiss anything that seems the same, so each paper must be evaluated with due care to ensure that truly valid questions get the full light of day.

"[Spencer] mind trick: You don't need to see any error bars. Move along." I like it Barry!

It would seem that Spencer has, academically, fallen very far now. reading Dessler's paper, it sounds like a teacher trying to explain something to a persistently errant pupil, which would be entertaining if the fallout were not so serious.

Camburn, sorry but it sounds rather like "I would rather believe Spenser than Dessler, so quick find something gives me hope". Now tell what you think the substance of McI criticism is (where the science is flawed because obviously Spenser's is) and let's resolve the matter.

Do you simply, uncritically just believe and parrot anyone says about climate science just b/c it rails against the actual science and data?

ClimateAudit was a fad, amongst other things. McIntyre. especially after the Wegman plagiarism affair and his role in the plagiarized Wegman report has no credibility anymore. Dr. Bickmore has responded to Mr. McIntyre's red herrings and strawmen. Really, Mr. McIntyre's 'analysis' amounts to nothing more than saying "look, squirrel!" to distract people from the implosion of Spencer's and Lindzens' papers. Well, I suppose someone had to step forward and try and create some uncertainty and doubt concerning Dessler (2010) and Dessler (2011).

Dr. Bickmore's comments:"Steve’s arguments are weak.

1. He reproduces Dessler’s stats, but complains the R^2 value is low. Well of course it is, because the slope is near zero. But Dessler did the right thing and calculated a 95% confidence interval. It is what it is.

2. He faults Dessler for complaining about Spencer and Braswell only using HadCRUT3, when Dessler had also used HadCRUT3. But what he doesn’t show is that it made any difference for Dessler’s analysis. In any case, I wouldn’t be so suspicious if this were the only problem with S&B, because they didn’t claim to analyze any other temperature series. They DID claim to analyze all 14 models, and **forgot** to report the results.

3. Finally, he shows that you can get a different slope by changing the lag time. But since Dessler and S&B had both said this in their papers, I’m not really impressed."

Of course Dessler is using HadCRUT, that is what the authors of the paper he is refuting used...duh! Moreover, unlike Spencer, Dessler used multiple datasets, and those data in fact corroborate each other...the outlier is Spencer's. Why? Because he cherry picked those data that would make the models look bad. Pretty telling that you are OK with that. Of course, McIntyre seems to neglect Spencer's and Lindzen's egregious errors (biased much Mr. McINtyre?). Actually think Dr. Bickmore is being very generous in how he is describing Mr. McIntyre's "critique" of Dessler's work.

The "skeptics" and those in denial about AGW are frantically trying to throw up smokescreens to save poor old Spencer, One has to wonder how long it will be before they "throw him under the bus" as Spencer is doing more harm than good for his cause right now and is rapidly becoming a liability.

Camburn, how you arrive at "Dessler was not good", while McIntyre's blog analysis was "quite good", all the while missing the train wrecks that are Lindzen and Choi (09) and Lindzen and Choi (2011) and Spencer and Braswell (2008) and Spencer and Braswell (2011) is beyond belief. In fact, doing so it is perfectly consistent with someone who is in denial.

Finally, can you even begin to explain to us what was "good" about McIntyre's "analysis"? We are waiting.

Here's a question - why is McIntyre "auditing" Dessler's work (and doing a piss-poor job of it), but not Spencer's or Lindzen's? I mean, Dessler's paper is basically an audit of Spencer and Lindzen. If McIntyre thinks Dessler's audit is flawed, why doesn't he do one of his own, as the self-proclaimed climate auditing expert?

Indeed we do :) Sadly "skeptics" here and elsewhere knowingly (or not) forget that rather blatant double standard. Really, this is now like amateur hour at the circus. A 'skeptic' at RC is now questioning the validity of the data that they all used. Denial at its finest.

It would be hilariously funny were it not for the fact that it is such a serious situation.

I followed Bickmore to MacIntyre and noted two things-
MacIntyre ducked key parts of Dressler's analysis, which in one sense is a good thing to admit his lack of knowledge, but then goes on to miss the point entirely- the point being that you can't make a case with present evidence for clouds doing much (short term) to influence the feedback one way or the other. Of course, if you are professionally peddling uncertainty, this isn't a point you want to talk about.